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Leaflet No. 430 

U. S. Department of Agriculture 

Cockroaches are pests through- 
out the United States. They carry 
filth on their legs and bodies and 
may spread disease by polluting 
food. They destroy food and dam- 
age fabrics and bookbindings. 

Cockroaches have an offensive 
odor that may ruin food. Unless 
dishes over which the insects run 
are thoroughly washed, they may 
give off the odor when warmed. 

There are about 55 kinds of cock- 
roaches in the United States, but 
only five kinds are troublesome in 
buildings. Most of the others live 
outdoors. They may enter houses 
by coming in on firewood or by fly- 
ing to lights, but most of them can- 
not develop indoors. They either 
leave or die. 

Those that do develop indoors 
are fairly easy to control in most 


Cockroaches have a broad, flat- 
tened shape, and six long legs. They 
are dark brown, reddish brown, 

light brown, or black. The adults of 
most species have wings. The young 
look like the adults, except that 
they are smaller and do not have 

Cockroaches hide during the day 
in sheltered, dark places. They come 
out and forage at night. If dis- 
turbed, they run rapidly for shelter 
and disappear through openings to 
their hiding places. 

The five kinds that are trouble- 
some in buildings can be distin- 
guished from each other by their 
appearance and by the places where 
they are found. The table and illus- 
trations will help you learn to dis- 
tinguish them. 


German and brown-banded cock- 
roaches mature in 4 to 6 months; 
other kinds mature in about a year. 

Cockroaches grow slowly when 
food, temperature, and moisture are 
unfavorable. Conditions are not 
usually ideal for rapid growth in 

American cockroach. (Natural size; 


some are 

Five Kinds of Cockroaches Troublesome in Buildings 



Where found 

American cockroach * 

Australian cockroach 2 

Brown-banded cock- 
roach 3 (also called 
tropical cockroach), 

German cockroach 4 
(also called croton 
bug and water bug) , 

Oriental cockroach 5 
(also called black 
beetle and shad 
roach) . 

Reddish brown to dark 
brown. Adults V/% to 2 
inches long. 

Reddish brown to dark 

brown. Yellow markings on 
the thorax; yellow streaks 
at base of wing covers. 
Adults 1 inch long. 

Light brown. Mottled, red- 
dish-brown wings on female 
lighter wings on male. 
Adults l /i inch long. 

Light brown. Black stripes 
running lengthwise on 
back. Adults % inch long. 
Most common of the five 

Black or dark brown. Traces 
of wings on females; short 
wings on males. Female 
adults 1 to \ l /i inches long; 
male adults a little shorter. 
More sluggish than other 
four kinds. 

Develop in damp base- 
ments and sewers; 
forage mostly on first 
floors of buildings. 

Develop in warm, damp 
places, in or out of 
doors; forage mostly 
on first floors of build- 

Develop and live all over 
the building. 

Develop and live all over 
the building, particu- 
larly in kitchens and 

Develop in damp base- 
ments and sewers; 
forage mostly on first 
floors of buildings. 

1 Periplaneta americana. 
s Blatta orientalis. 

2 Periplaneta australasiae. 3 Supella supelledilium. 

Blattella germanica. 

buildings and homes where good 
sanitation is practiced. 

The female lays her eggs in a 
leathery capsule, which she forms 
at the end of her body. The German 
cockroach carries the egg capsule 
about a month, and drops it a day 
or so before the eggs are ready to 
hatch; about 30 cockroaches hatch 
from the capsule. The other kinds 
carry the egg capsules a day or two, 
then glue them to some object in a 
protected place; about 12 cock- 
roaches hatch from each capsule 
after an incubation period of 2 to 
3 months. 


Cockroaches may enter the house 
from outdoors, in infested contain- 
ers from other buildings, or from 
adjoining homes or apartments. To 
keep them out, fill all cracks passing 
through floors or walls, and cracks 
leading to spaces behind baseboards 
and door frames, with putty or 
plastic wood. Pay special attention 
to water and steam pipes entering 

Cockroaches develop in large 
numbers in dirt and filth. Thorough 
cleaning reduces the likelihood of 
heavy infestation. 


When you bring baskets, bags, or 
boxes of food and laundry into the 
house, look for cockroaches that 
may be hiding in them, and kill any 
that you find. 


Infestations can be controlled by 
applying insecticides in sprays and 

Make limited applications; do 
not treat entire floors, walls, or ceil- 
ings. Treat only along baseboards, 
under cupboards, and in similar 
places where roaches hide. Do not 
treat surfaces used for the prepara- 
tion of food. Do not treat storage 
spaces that contain food. 

The following list names the most 
commonly used insecticides, gives 
the proper strength of each spray 
or dust, and indicates the effective- 
ness of each. Dusts can be bought 
already prepared. So can most 
sprays; others can be prepared 
easily by following the directions 
on the label. 

Chlordane: 2-percent oil solu- 
tion or water emulsion; or 5-per- 
cent dust. . . . Highly effective 
against all cockroaches except those 
that have developed resistance to 

Diazinon: 0.5-percent oil solu- 
tion or water emulsion. (See "Re- 
sistant Roaches," page 6.) 

Lindane : 0.5-percent oil solution 
or water emulsion; or 1 -percent 
dust. . . . Effective against all 
cockroaches except those that have 
developed resistance to insecticides. 

Duration of effectiveness shorter 
than that of chlordane. 

Malathion: 2-percent oil solu- 
tion or water emulsion; or 4- or 5- 
percent dust. (See "Resistant 
Roaches," page 6.) 

Ronnel: 2-percent oil solution 
or water emulsion. (See "Resistant 
Roaches," page 6.) 


Oriental cockroach: Above, female; below, 
male. (1% times natural size.) 

These insecticides kill the cock- 
roaches present and leave a residue 
on the treated surface. The residue 
does not keep cockroaches out, but 
those that come in contact with it 
are killed. A single treatment in the 
right places gives protection for 
several weeks. 

A liquid insecticide is often the 
best for use in the home. A dust or 
water-base spray may be used when 
there is danger of fire from oil-base 
liquids. Both a liquid and a dust 
may be used when cockroaches are 
abundant, difficult to control, or 
firmly established. 

Baygon, trichlorfon, and fenthion 
are effective, but application of tri- 
chlorfon and fenthion is limited 
to spot treatment by professional 
pest -control operators. 


Whether spray or dust is used, 
treatment should be limited to base- 
boards, cracks, and places where 
roaches hide. 


Apply a liquid insecticide with 
an ordinary household plunger- 
type sprayer that produces a coarse 
spray to wet the surface being 

Mention of a proprietary product in 
this publication does not constitute a 
guarantee or warranty of the product by 
the U.S. Department of Agriculture and 
does not imply its approval by the Depart- 
ment to the exclusion of other products 
that may also be suitable. 



Female Australian cockroach. (l l / 2 times 
natural size.) 

treated. If the mist is too fine, it will 
float away in the air. Apply enough 
spray to moisten surfaces thor- 
oughly, but not so much that the 
liquid begins to drip or run. 

Professional pest-control opera- 
tors may use larger sprayers, but 
should make spot treatments only. 

A paintbrush may be used for 
applying the liquids in cracks or 
along baseboards. 


Apply an insecticide dust with a 
puff duster of the bulb, plunger, or 
bellows type. Blow the dust into 
hiding places that are hard to reach 
with a spray and onto surfaces 
where roaches run. A light, uniform 
film is sufficient. Repeat when mois- 
ture causes the dust to cake. 

Placing a band of dust on the floor 
around the edges of a room is not an 
adequate treatment. Many roaches 
may be able to go from their hiding 
places to sources of food and water 
without crossing the band of dust. 

Resistant Roaches 

Roaches develop resistance to 
chlordane and lindane; resistance 
is especially widespread in German 

Diazinon, ronnel, and malathion 
will control resistant roaches. Apply 
diazinon in spot treatments only 
over the infested places as a 0.5 -per- 
cent emulsion or oil solution spray. 
Malathion may be used at 2- to 3- 
percent strength in similar formula- 
tions. Ronnel may be used at 
2-percent strength. 


For best results, apply insecticides 
to places where cockroaches hide. 

To find the hiding places, enter 
a dark room quietly, turn on the 
lights, and watch where the cock- 
roaches run. 

They may hide — 

Around the kitchen sink and 

In cracks around or underneath 
cupboards and cabinets, or in- 
side them — especially in upper 

Around pipes or conduits, where 
they pass along the wall or go 
through it. 

Inside the motor compartment 
of mechanical refrigerators. 

Behind window or door frames. 

Behind loose baseboards or mold- 
ing strips. 

On undersides of tables and 

In radio and television cabinets. 

Behind mirrors. 

On closet and bookcase shelves. 

When treating cupboards and 
pantries, take everything from 
shelves and remove drawers so that 
food and utensils will not become 

Spray or dust the interiors. Al- 
low the spray to dry, or clean up ex- 
cess powder. Clean shelf surfaces, 
or cover them with paper, before 
replacing the articles. 

If drawers are cleaned thor- 
oughly, it is not necessary to spray 
inside them; it will help to spray 
the sides, backs, and undersurf aces. 


Bait containing either Kepone or 
Baygon may be used in cockroach 
control. Purchase such a bait and 
place it in areas frequented by cock- 
roaches. Do not use it in places 
where it can be reached by children 
or pets. 


Brown-banded cockroach: Above, female; 
below, male. (\ l / 2 times natural size.) 


German cockroach: A, First stage; B, second stage; C, third stage; D, fourth stage; E, adult 
female; F, female with egg case; G, adult with wings spread, (l 1 /^ times natural size.) 


Fumigation immediately destroys 
a roach infestation, but it is danger- 
ous in congested or commercial 
areas, and it is expensive. Also, 
buildings in such areas are likely to 
become reinfested within a short 

Since effective residual insecti- 
cides have become available, fumi- 
gation is seldom used. Only a pro- 
fessional pest-control operator 
should fumigate. 

Boric acid and borax 

Finely powdered boric acid and 
borax (sodium tetraborate penta- 
hydrate) act slowly and are gen- 
erally less effective than other insec- 
ticides against cockroaches. 

These materials are sometimes 
mixed with ingredients that are at- 
tractive to cockroaches, and com- 
pressed into tablets to be used as 
bait. The powders or bait tablets 
may give satisfactory results when 
used in places where there is little 

food for cockroaches, such as in of- 
fice buildings. 


Pesticides used improperly can be 
injurious to man, animals, and 
plants. Follow the directions and 
heed all precautions on the labels. 

Store pesticides in original con- 
tainers — out of reach of children 
and pets — and away from foodstuff. 

Apply pesticides selectively and 
carefully. Do not apply a pesticide 
when there is danger of drift to 
other areas. Avoid prolonged in- 
halation of a pesticide spray or 
dust. When applying a pesticide it 
is advisable that you be fully 

Do not apply oil sprays where 
they could be ignited by a flame 
(for example, the flame of a pilot 
light) or by electric sparks. 

Do not use lindane, diazinon, 
ronnel, or chlordane to treat an 
entire room. Restrict the use of these 
insecticides to places where roaches 
run or hide. 

After handling a pesticide, do not 
eat, drink, or smoke until you have 
washed. In case a pesticide is swal- 
lowed or gets in the eyes, follow the 
first aid treatment given on the 
label, and get prompt medical atten- 
tion. If a pesticide is spilled on your 
skin or clothing, remove cloth- 
ing immediately and wash skin 

Dispose of empty pesticide con- 

tainers by wrapping them in sev- 
eral layers of newspaper and plac- 
ing them in your trash can. 

NOTE : Registrations of pesti- 
cides are under constant review by 
the U.S. Department of Agricul- 
ture. Use only pesticides that bear 
the USDA registration number and 
carry directions for home and 
garden use. 

Prepared by 

Entomology Research Division 



. KrutUM 01 M IKHIWI 

Washington, D.C. 

Revised September 1970 

For sale by the Superintendent of Documents, U.S. Government Printing Office 
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